1. Technical Field
The present invention relates to a printer configured to print on a print medium.
2. Related Art
Information codes are known, such as a barcode or a two-dimensional code typified by a QR code (registered trademark). In view of high-mix, small-lot production, on-demand printing is drawing attention for printing an image of an information code (a code image) on paper or the like. In particular, a line inkjet head printer, with which high-speed printing is easy, is expected to be used to print a code image.
An information code represents information by, for example, the widths of bars or the arrangement of cells that constitute the code. Hence, if the widths of the bars in a printed barcode are different from prescribed widths, the barcode readability by a reader is degraded. For this reason, high printing accuracy is required in code image printing.
In printing such as inkjet printing which forms an image on a print medium by use of dots, the dots tend to increase in their size due to, for example, bleeding of ink. For this reason, when a barcode is printed using an inkjet printer for example, the barcode readability by a reader might be degraded due to bleeding of ink which makes the widths of the bars larger than the prescribed widths. When the barcode is printed on a sheet on which ink easily bleeds, the above-mentioned problem of the degradation in the barcode readability occurs more likely.
To overcome such a problem, it is known to reduce the amount of ink ejected by an inkjet printer to form one dot when it prints a code image. Moreover, Japanese Patent Application Publication No. 2003-237059 discloses an inkjet printer which reduces the amount of ink ejected for dots in an edge portion of each print region of a code image from the amount of ink ejected for the other dots.
By thus reducing at least the amount of ink ejected for dots in the edge portions among the dots forming a code image and thereby decreasing the size of these dots, for example, the bars of the code image are prevented from being printed wider than the prescribed widths.